The analgesic activity and possible mechanisms of deacetyl asperulosidic acid methyl ester from Ji shi teng in mice

Deacetyl Asperulosidic Acid Methyl Ester (DAAME) from Ji shi teng was evaluated on analgesic activity in mice using chemical and thermal models of nociception. Given intraperitoneally, DAAME, at doses of 40 and 80 mg/kg, produced significant inhibitions on chemical nociception induced by intraperitoneal acetic acid, subplantar formalin/capsaicin injections and on thermal nociception in the tail-flick test and in the hot plate test. In the open-field test and the rotarod test, DAAME couldn't impair the motor performance, indicating that the observed antinociception was unlikely due to motor abnormality. In a measurement of core body temperature, DAAME (80 mg/kg) did not affect temperature within 80 min. Moreover, DAAME-induced antinociception in the capsaicin test and the hot plate test was significantly antagonized by glibenclamide. The results suggested that DAAME-produced antinociception was possibly involved in the ATP sensitive K+ channels in the capsaicin test and the hot plate test, which merited exploring further.